Multitubular heat exchanger



May 11, 1965 A. CHRIST MULTITUBULAR HEAT EXCHANGER Filed Dec. 26, 1962 n if INVENTOR. A] red Chrisi United States Patent 3,182,719 MULTITUBULAR HEAT EXCHANGER Alfred Christ, Zurich, Switzerland, assignor to Escher Wyss Ahtiengesellschaft, Zurich, Switzerland, a corporation of Switzerland Filed Dec. 26, 1%2, Ser. No. 247,043 Claims priority, applicatzign/switzerland, Jan. 10, 1962,

Claims. (Cl. 165-111) This invention relates to a multitubular heat exchanger heated by condensing steam, having a chamber and a bundle of vertical or inclined tubes arranged therein through which a heat-absorbing medium flows.

In known heat exchangers of this kind, the heating steam is introduced laterally into said chamber and is then distributed partly in cross-flow and partly in longitudinal flow over the surface of the tubes to be heated, certain steam passages being if necessary left free for facilitating the distribution of the stream in the transverse direction in the tube system. It has, however, been found that in such a case satisfactory venting of the steam chamber is not possible. At individual points, stagnant airaccumulations may form and impair the heat transfer. Since these air accumulations occur irregularly at any parts of the tube system, it is often quite impossible to remove them.

It is the object of the invention to obivate this disadvantage. In a heat exchanger of the kind hereinabove described, this is achieved according to the invention in that the chamber is provided with a partition, situated in the vinicity of its upper boundary and extending transversely of the tubes, the latter passing through said partition with clearance, and in that furthermore the heating steam supply pipe opens into the chamber above this partition, and the air-venting pipe is connected in the vicinity of the lower boundary of the chamber.

In this way, in the part of the chamber situated above the partition, distribution of the heating steam over the entire cross-section of the chamber is enforced. The rate of flow of the steam is here everywhere so high that no stagnant accumulations of gas can form. The steam then flows through the clearance left between the tubes and the partition into the lower part of the chamber. In this lower part, the steam flows downwardly uniformly distributed over the chamber cross-section. Air or other gases contained in the steam can therefore only accumulate in the vicinity of the lower boundary of the chamber, that is to say where the air-venting pipe is connected. The removal of these gases then presents no difficulty.

A constructional example of the subject of the invention is shown in simplified form in the drawing, wherein:

FIGURE 1 shows a vertical section through the heat exchanger on the line 1-1 of FIGURE 2, certain parts being omitted in the interest of clarity, and

FIGURE 2 a cross-section on the line II--II of FIG- URE 1.

FIGURES 3, 4 and 5 show details of FIGURE 1 on a larger scale.

FIGURE 6 is a fragmentary sectional view on line 6-6 of FIGURE 1 and showing the displacement body omitted from FIGURE 1.

The heat exchanger shown may serve for example for the supply of heat to a liquid which is to be evaporated. A cylindrical shell 1, an upper end plate 2 and a lower end plate 3 form a chamber 4. Arranged in this chamber 4 is a bundle of spaced apart vertical tubes 5 extending in parallel relationship through the chamber 4 from the upper to the lower end plate. A heat absorbing medium passes from a space 6 situated below the end plate 3 into the tubes 5, flows upwardly through these tubes into a space 7 situated above the end plate 2 in order finally to return to the space 6 through a central tube 8. The heat absorbing medium is circulated in the manner described either by natural convection or in forced manner by pumping means, not shown.

In its upper part, the chamber 4 is provided with a horizontal partition 9 situated in the vicinity of its upper boundary, namely the end plate 2. This partition 9 is arranged between the end plates 2 and 3 so as to divide the chamber 4 into a relatively small upper space and a relatively large lower space. The tubes 5 are expanded or welded tightly in the end plates 2 and 3, but pass with a certain clearance s, as shown in FIGURE 4, through the partition 9 extending transversely of the tube 5.

A connection 10 for the heating steam supply pipe opens into the chamber 4 above the partition 9. Venting pipes 11 are connected in the vicinity of the end plate 3 forming the lower boundary of the chamber 4. A connection 12 serves for the discharge of condensate from the lower space of chamber 4. In the region of the steam-supply pipe 10, a tube-free steam passage 13 is provided, which is screened from the adjacent tubes 5 by perforated plates 14 and permits unimpeded access of the steam to the interior of the chamber 4. The steam then passes from the space of the chamber 4 situated above the partition 9 through the clearance s between the tubes 5 and the partition 9 into the underlying space of the chamber 4. The clearance s is advantageously so dimensioned that the drop in pressure of the heating steam on flowing through this clearance is greatly than the difference in pressure between the heating steam inlet, that is to say, the connection 10 and the point opposite this place in the upper space of the chamber 4. An approximately uniform distribution of the stream over the entire tube system on passing through the partition 9 is thereby obtained.

In the lower space of the chamber 4 the tube-free passage is advantageously filled by a displacement body 15 (see FIGURE 6), so as to preserve the uniform steam flow as far as possible.

A further improvement in regard to uniform steam distribution is obtained if instead of having only one steam supply pipe 10, two or more thereof are distributed on the periphery of the part of the chamber situated above the petition.

The effect described can also be substantially achieved if the tubes 5 of the heat exchanger are not vertical but are inclined to the vertical direction.

What is claimed is:

1. A multitubular heat exchanger for the transfer of heat from condensing steam to a heat absorbing medium comprising a shell; an upper and a lower end plate forming with said shell a chamber; a partition substantially parallel with and arranged between said end plates so as to divide said chamber into a relatively small upper space and a relatively large lower space; a bundle of spaced apart tubes extending in parallel relationship through said chamber from said upper to said lower end plate so that all of said tubes traverse said partition; the said partition having perforations dimensioned so that each tube passes through a corresponding perforation with clearance; at least one supply connection for the supply of the steam to said upper space, the steam, in order to enter into the lower space, being constrained to flow along longitudinal flow paths defined by the clearances between the tubes and the perforations through which they pass and thence longitudinally along the corresponding tube surface; flow connections for the circulation of a heat absorbing medium through said tubes; a discharge connection for the discharge of condensate from said lower space; and a venting pipe issuing from said lower space in the vicinity of the lower end plate.

2. The combination defined in claim 1 in which the tubes of the bundle are disposed so as to leave a tube-free passage for the steam from the steam supply connection toward the interior of the upper space of the chamber.

3. The combination defined in claim 2 in which perforated plates are arranged toscreen said tube free passage from the adjacent tubes.

4. The combination defined in claim 2 in which a displacement body is arranged in the lower space so as to fill the tube free passage.

5. A multitubular heat exchanger for the transfer of heat from condensing steam to a heat absorbing medium comprising a shell; an upper and a lower end plate forming with said shell a chamber; a partition arranged between said end plates so as to divide said chamber into a relatively small upper space and a relatively large lower space; a bundle of spaced apart tubes extending in parallel relationship through said chamber from said upper to said lower end plate so that all of said tubes traverse said partition; the said partition having perforations dimensioned so that each tube passes through a corresponding perforation with clearance; at least one supply connection for the supply of the steam to said upper space, the steam, in order to enter into the lower space, being constrained to flow along longitudinal flow paths defined by the clearances between the tubes and the perforations through which they pass and thence longitudinally along the corresponding tube surface; said clearance being so dimensioned that steam from said upper space on flowing through said clearance undergoes a pressure drop greater than the difference in pressure between the supply connection and the point opposite it in the upper space of the chamber; flow connections for the circulation of a heat absorbing medium through said tubes; a discharge connection for the discharge of condensate from said lower space; and a venting pipe issuing from said lower space in the vicinity of the lower end plate.

References Cited by the Examiner UNETED STATES PATENTS 1,894,760 1/33 Dodd 165110 2,204,497 6/40 Hunter 165--111 2,494,767 1/50 Lindsay 122 34 2,995,341 8/61 Danesi 165-410 3,074,480 1/63 Brown et al. 165-160 CHARLES SUKALO, Primary Examiner.

FREDERICK L. MATTESON, ]R., Examiner. 

1. A MULTITUBULAR HEAT EXCHANGER FOR THE TRANSFER OF HEAT FROM CONDENSING STEAM TO A HEAT ABSORBING MEDIUM COMPRISING A SHELL; AN UPPER AND A LOWER END PLATE FORMING WITH SAID SHELL A CHAMBER; A PARTITION SUBSTANTIALLY PARALLEL WITH AND ARRANGED BETWEEN SAID END PLATES SO AS TO DIVIDE SAID CHAMBER INTO A RELATIVELY SMALL UPPER SPACE AND A RELATIVELY LARGE LOWER SPACE; A BUNDLE OF SPACED APART TUBES EXTENDING IN PARALLEL RELATIONSHIP THROUGH SAID CHAMBER FROM SAID UPPER TO SAID LOWER END PLATE SO THAT ALL OF SAID TUBES TRAVERSE SAID PARTITION; THE SAID PARTITION HAVING PERFORATIONS DIMENSIONED SO THAT EACH TUBE PASSES THROUGH A CORRESPONDING PERFORATION WITH CLEARANCE; AT LEAST ONE SUPPLY COLNNECTION FOR THE SUPPLY OF THE STEAM TO SAID UPPER SPACE, THE STEAM, IN ORDER TO ENTER INTO THE LOWER SPACE, BEING CONSTRAINED TO FLOW ALONG LONGITUDINAL FLOW PATHS DEFINED BY THE CLEARANCES BETWEEN THE TUBES AND THE PERFORATIONS THROUGH WHICH THEY PASS AND THENCE LONGITUDINALLY ALONG THE CORRESPONDING TUBE SURFACE; FLOW CONNECTIONS FOR THE CIRCULATION OF A HEAT ABSORBING MEDIUM THROUGH SAID TUBES; A DISCHARGE CONNECTION FOR THE DISCHARGE OF CONDENSATE FROM SAID LOWER SPACE; AND A VENTING PIPE ISSUING FROM SAID LOWER SPACE IN THE VICINITY OF THE LOWER END PLATE. 